There are much better knots for fishing that are just as easy to tie. The palomar knot and the uni-knot cover just about every option one would need, and they are both stronger knots and more secure knots (less slipping), especially when braided line is in use.

I have been using different types of RAM mounts over the years. The GPS unit on my boat has been using a RAM mount for years, and even in rough conditions, it does nothing more than just shake a little bit.